1. Field of the Invention
The present invention relates to a belt-drive device including meandering prevention members for controlling the meandering of a belt wound on a roller in the direction of a rotational axis, as well as an image forming apparatus including the same.
2. Description of Related Art
Conventional belt-drive devices of this type are used in, for example, belt fusers included in image forming apparatuses, as described in Japanese Patent No. 4691425. Such a belt-drive device includes a heating roller on which a fusing belt is wound, and the heating roller is subjected to, for example, cutting work such that the outer diameter of the heating roller is smaller at each end than at the center, and therefore, the heating roller is stepped at each end portion. Moreover, the end surface of the stepped portion abuts on an end surface of a belt meandering prevention member. As a result, the fusing belt is prevented from becoming stuck in a gap between the inner circumferential surface of the belt meandering prevention member and the outer circumferential surface of the heating roller, which might be caused due to dimensional error, thermal expansion, etc., of the meandering prevention member.
In recent years, to meet energy saving demand, the fuser is required to have a heating roller with low heat capacity. To achieve the low heat capacity of the heating roller, it is effective to reduce the volume of the heating roller. More specifically, it is effective to reduce the outer diameter of the heating roller.
Furthermore, not only the fuser but also various other devices use the belt-drive device. In such devices also, rollers are desired to have small diameters.